Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~13~3'~8
The invention concerns a sack made of a textile which is itself made of a
hollow web
fabric, of which two superimposed layers, forming the front and back of the
sack, are
connected with each other at the sides and bottom by a fabric splice, a length
of fabric
for sacks which includes a two-ply fabric which has a continuous fabric splice
connecting both layers of the two-ply fabric on one edge in the direction of
the warp
threads and which has fabric splicing strips which include centre selvedges at
intervals
corresponding to the width of the sack connecting both layers of the two-ply
fabric,
and a procedure for manufacturing the fabric for sacks in a single production
process
on a standard loom or on an automatic loom fitted with a dobby.
Up to now, either loosely-woven sacks made of man-made base materials or of
closely-woven standard natural base materials have been used for storing and
carrying
fruit, vegetables and the like.
Production processes for sacks made of man-made base materials, e.g. of
plastic film
or plastic fibres knitted on knitting machines are very common nowadays, but
when
allowance is made for the fact that the edges of such sacks are connected
thermally,
such processes are not suitable for manufacturing sacks made of natural
textiles, e.g.
100% cotton. However, the production of sacks from natural, combustible and
bio-
degradable textiles is particularly desirable, especially for reasons of
environmental
protection.
A production process for textile sacks made of natural base material usually
takes
place in three phases:
1. The material for the body of the sack is knitted on special Raschel
knitting
machines;
2. The body of the sack is cut to the desired sizes from the knitted material;
3. The sacks are sewn together and the edges stitched.
A procedure for manufacturing woven sacks on a standard loom with a dobby
control
system for the warp threads to create a leno (or doupe or gauze) weave is
known from
EP 0 408 467 A1. A two-ply fabric is manufactured by this process, the two
superimposed, separate leno fabric layers of which are connected to each other
by the
intertwining of their respective warp and weft threads along one edge in the
direction
of the warp and across the entire width at regular intervals in the direction
of the weft.
In this way a connected length of consecutive sacks is obtained, joined
together
transversely and along one selvage, whereby the other selvage remains open.
Such a
strip of sacking is also suitable for automatic filling of the sacks, whereby
the sacks are
separated from each other along the middle of the respective transverse
connection
area, after they have been filled and closed.
1
CA 02135378 1999-10-19
The purpose of the invention is to create a textile sack and length of fabric
in the form of a roll
for such sacks, in which it should be possible to manufacture the sacks or
fabric in a simple,
cost-ef~'ective way, and the sacks should be easy to handle and also well
suited to mechanical
filling.
The sack in accordance with the invention is characterised by the fact that
the two layers of
fabric forming the front and back of the sack are joined at the sides and
bottom by a fabric
splice and both have a shoulder consisting of a fabric splice, whereby the
fabric splices at the
sides, connecting the front and back of the sack, extend from the fabric
splice at the bottom at
least to the shoulder.
The sack, which should preferably be made of a natu~.ral textile on a standard
loom or on an
automatic loom fitted with a dobby in a single production process, has a long
life and an
attractive appearance, the more so as the body of the sack itself can also
very easily be woven
in different patterns. The edges of the sack and the selvedges will not fray
and, moreover,
have no seams which could open. The woven sacks :require no further processing
and the
finished sacks taken off the loom can be filled immediately.
The inventive sack may also include apertures for lifl:ing or closure strips
provided in or
woven into its shoulders.
In accordance with a further feature of the invention, the sack can also be
characterised by the
fact that its front and back are loosely woven whilst the fabric splice
connecting both layers of
the fabric at the sides and bottom and the fabric splice forming the upper
shoulder are of a
denser weave. This not only gives the sack a pleasing; appearance, but the
body of the sack
itself is also thus sufficiently air-permeable and its edges are stable and
will not fray.
Another aspect of the invention relates to a length of fabric for sacks, which
is characterised
by the fact that the two-ply part of the fabric has shoulders terminating both
its layers at the
other edge and that the centre selvedges connecting the two layers of the two-
ply fabric extend
at least from the continuous fabric splice provided at one edge to the
shoulders terminating
each of the two layers of the two-ply fabric provided at the other edge.
2
CA 02135378 1999-10-19
Such a length of fabric, particularly if made of a natural textile, for
example cotton, can be
manufactured very advantageously from a technological aspect as well, on a
normal loom or
on an automatic loom fitted with a Bobby, as a roll, consisting of a large
number of sacks.
Depending on the use, the length of fabric can be cut into pieces immediately
along the centre
selvedge, to obtain individual sacks, or, in the case of major industrial or
commercial use, the
rolled length of fabric can be fed into an automatic filling machine so that
the sacks can be
filled. After a sack has been filled they are closed by sewing up the
shoulders or flaps, or
using the closure strips provided in the shoulders, and separated from the
fabric at the centre
selvedge, e.g. by mechanical rotary knives.
In accordance with the invention, a fabric may, depending primarily on the
facilities on a
loom, include two or more lengths of fabric made up as above, in which case,
however, one is
arranged as a mirror image of the adjacent strip. In this case the fabric
splicing strips
extending in the direction of the warp simultaneously form centre selvedges.
The invention also concerns a procedure for manufacturing a length of fabric
for sacks which
is characterised by the fact that a connection between the layers of the two-
ply fabric is woven
continuously in a repeated sequence of three groups of shaft threading,
consisting of
- the shoulders in the form of a splicing fabric terminating both the layers
of the two-ply
fabric extending in direction of the warp threads at one edge, remaining open,
of the length of
fabric comprising a two-ply fabric in the first group;
- the two-ply fabric forming the material of the body of a sack and the
connection, at
regular intervals, of both the layers of the two-ply fabric in the form of a
splicing fabric strip
normal ly extending to the edges of the two-ply fabric and in direction of the
weft threads,
including one centre selvedge separating the sacks in the second group;
- and a connection of the layers of the two-ply fabric formed from a splicing
fabric
extending along the other edge of the length of fabric opposite the edge
remaining open in
direction of the warp threads in the third group.
The manufacture of the fabric, and thus of the sacks tlhemselves, takes place
in a way which is
both economically and technologically advantageous, in a single production
process, in which
there are three types of weave within the entire width of the fabric, namely
hollow web fabric,
two-ply fabric and normal shaft weave. There is also a great advantage in that
the
CA 02135378 1999-10-19
manufacture of sacks by this method is faster than was previously possible and
that it can also
take place using natural, environmentally-friendly base materials. In
addition, the procedure
can also be implemented in any pattern, depending upon the facilities of the
dobby, without
resulting in increased production costs. Sacks manufactured in this way are
thus not only
usable for the storage and can iage of, for example, fruit and vegetables, but
also for display
and decorative purposes. Finally, the inventive procedure is more favourable
than the usual
multiphase manufacturing process for traditional sacks with regard to the
material and energy
required.
A further characteristic of the inventive procedure is that the connection
formed at one edge of
the two-ply fabric is a continuous fabric splice and that the shoulders
terminating both the
layers at the other edge of the fabric are both separate splicing fabric
strips forming sack flaps.
This version of the fabric strip not only represents a measure advantageous to
production, but
the continuous, separate shoulders or flaps terminating both layers of the
fabric in particular
facilitate complication-free, automatic machine filling of the sacks in a
particularly simple
way.
The invention also includes a procedure for manufacturing a length of fabric
including two or
more lengths for sacks, manufactured on a loom or on an automatic loom fitted
with a dobby,
continuously, in a single production process, by threading the shafts in a
repeated sequence of
three groups, in accordance with the stated procedurc: for a fabric strip
containing one row of
sacks, in an adjacent, mirror-image way, with the centre selvedges running in
the longitudinal
direction of the fabric strip being formed into adjoining fabric splicing
strips and/or shoulders.
The subject of the invention is elucidated by the enclosed drawings, in which
Fig. 1 shows a
draft, Fig. 2 a view of a section of the inventive fabric from above, Fig. 3 a
front view of a
partially opened inventive sack, Fig. 4 an oblique view of a section through a
length of
inventive fabric split apart and Fig. 5 a section along the line A - A through
the fabric as
shown in Fig. 4.
3a
CA 02135378 1999-10-19
The manufacture of sacks or fabric for sacks takes place on traditional looms
and, in
accordance with a further development, is possible on a modern automatic loom,
provided that said automatic loom is fitted with a dobby. The loom or
automatic loom
titted with a dobby can either be controlled lby punch cards (drafts) or
computer
(microprocessor).
For specific reasons of environmental compatibility the sacks should be made
oi~
natural, environmentally-friendly base materials, such as cotton, jute, hemp,
flax or
linen, sisal, wool and similar natural fibres, but preferably of 100% cotton,
so that
burning or composting sacks which are no lonl;er usable and are to be thrown
away
does not present any problems. For this reason such sacks are also known as
"bio-
sacks" .
The manufacture of the sack or fabric takes place on dobbies controlled by
punch cards
in accordance with the draft in Fig. 1, whereb~r the weaving of the centre
selvedges
separating the sacks from each other takes placf: using a separate card
control system.
It will be seen from the drawing of the punch card and the following details
of the
production technique that the shaft threading takes place in groups, whereby
how often
each group is repeated depends on the dimensions of the sack.
There are three different shaft threading groups:
- the first group includes the sack loops and/or the upper shoulders of the
sack ;
- the second group includes the material of the; body of the,sack (two-ply
fabric) and
the connection between the layers of the tvvo-ply fabric which itself includes
the
centre selvedge that separates the sacks;
- the third group includes the edge or the connection of the two-ply fabric at
the
bottom of the sack.
Ten shafts are required for weaving. Reeding takes place with 140/10 cm reeds
with
four threads. The lift of the shafts depends on the punch card holes and
repetition is
determined by the dimensions of the sack.
The special feature is that whilst one edge of the two-ply fabric is closed,
the other
edge is open, and there is a hollow weave fabric in the middle. Sacks woven in
this
way require no further processing and can be: used immediately for their
intended
purpose.
Three stipulated examples, A, 13 and C of the production technology are given
below
for further elucidation of the inventive procedur~°:
4
iAl~~3~8
EXAMPLE A:
Triple row of sacks, 50 cm, 40 cm, 33 cm
Type of loom: P-155
Warp: 50 cm run 434 threads, of which 2 x 32 edge
40 cm run 360 threads, of which 2 x 32 edge
33 cm run 308 threads, of which 2 x 32 edge
total 1,102 threads
Tie up on shaft frame 4 + 2, in accordance with draft as
shovm in Fig. 1
Number of reeds 70/10 cm bar reed
Base 4 threads, 3 teeth remain empty
Then another 4 threads
Edge with 4 threads
Weave in accordance with draft as shown in
Fig. 1
Threading width -136.4 + 1.2 + 0.8
Width in the grey 50 cm, 40 cm, 33 cm
L/V adjustment 70/140
Warp threads 50 tex x 2
Weft threads 29.5 tex x 2
Designation of thread 13.3/ 12.1
N L/V
Designation of fabric 465/847
N L/V
Surface density 159 g/m2
Fabrication 4%
Shrinkage S%
Capstan gear interval 138 cm
Roll length 100 linear metres, possibly in accordance
with
instructions issued
~:;13a3 r 8
EXAMPLE B:
Triple row of sacks, SO cm, 40 cm, 33 cm
Type of loom: P-155
Warp thread: 50 cm run 804 threads, of which 2 x 32 edge
40 cm run 656 threads, of which 2 x 32 edge
33 cm run 552 threads, of which 2 x 32 edge
total 2,012 threads
Tie up on shaft frame 4 + 2, in accordance with draft as
shown in Fig. 1
Number of reeds 70/ 10 cm bar reed
Base 4 threads, 1 tooth remains empty
Then another 4 threads
Edge with 4 threads
Weave in accordance with draft as shown in Fig.
1
Threading width -136.4 + 1.2 + 0.8
Width in the grey 50 cm, 40 cm, 33 cm
L/V adjustment 140/140
Warp threads 29.5 tex x 2
Weft threads 29.5 tex x 2
Designation of thread 12.1/12.1
N L/V
Designation of fabric 84/84
N L/V
Surface density 171 g/m2
Fabrication 4%
Shrinkage 5 %
Capstan gear interval 138.1 cm
Roll length 100 linear metres, possibly in accordance
with
instructions issued
Warping 500 linear metres
6
CA 02135378 1999-10-19
CXAMPLE C:
Sack, 2 x 60 cm
Type of loom: Chinese 175
Total warp threads: 1,744
Of which edge: 2 x 32 threads per run
Tie up In accordance with draft as shown in Fig. 1
Reeding Spring reed 14-0/10 cm
Four threads on every fourth reed gap
Threading width 2 x 60 cm. Tvro reed combs remain empty between
the runs.
Width in the grey 2 x 60 cm
L/V adjustment 140/120
Warp threads 29.5 tex x 2
Weft threads 19.5 tex x 2
Fabrication (loss) 1 %
Shrinkage 1 %
Thread waste 3%
Designation of thread N L/V 6.1/6.1
Designation of fabric N L/V 420/360
Surface density 150 g/m2
Weave In accordance with the draft shown in Fig. 1
Capstan gear interval 120 cm
Figs. 2 and 4 show a section of a fabric for sacks, whereby centre selvedges 1
separating the sacks from each other are provided at right angles to the
longitudinal
direction of the strip. Continuous sacking flaps. or shoulders 2 are provided
on one
edge of the fabric. 3 designates the actual body of the sack and 4 a space for
publicity,
though an aperture could also be provided at this point for lifting. The
shoulders 2 have
a point S at which they meet the body of the sack 3, providing a facility for
sewing up a
full sack. Centre selvedge 1 is located in the centre of a part 6 of the two
layers of the
two-ply fabric which have been woven together, whereby said part 6 is
terminated by
edges 7. At the edge of the fabric opposite shoulders 2 is a continuous length
of fabric
8, connecting both the layers of the fabric, thus closing the bottom of the
sacks.
9 designates the cavity of the sack, which has a front 10 and a back 11 (Figs.
3 and 5).
The production of the sack or length of fabric for sacks takes place on a loom
under the
conditions already described, in any pattern, depending on the dobby. The
production
sequence is, as previously mentioned, such that, due. to shaft threading in
three groups, the
machine weaves the design of the sack loops or shoulders (2) in a denser weave
in the first
group, to terminate each of the two layers of the two-ply fabric on an edge of
the length of
fabric remaining open. In the second group, the body of the sack (3) is woven,
usually in a
7
CA 02135378 1999-10-19
looser weave, in the form of a two-ply fabric. In addition, the machine weaves
the front 10
and back 1 I of the sack in accordance with the instmctions which it has been
given on the
punch card, i.e. both the fabric layers of the two-ply fabric are woven
together in the
production sequence, whereby centre selvedge 1, which separates the individual
sacks from
each other, is formed between the edges 7 of the parts woven together 6 thus
formed. Due to
the third group of shaft threading, the weaving of the trvo layers of the
fabric on the other edge
of the length of fabric opposite the edge remaining of~en takes place
continuously during the
production process, forming a closely woven fabric splicing strip 8, which
closes the end of
the sack. In the vicinity of the point at which they meet the body of the sack
3, two preferred
points 5 are situated in the shoulders 2, at which the sack can be sewn closed
after filling. The
shoulders also provide space 4 for the application of publicity or apertures
for lifting.
By using this uniform production process, sacks with a cavity 9 are obtained.
As a
result of the production sequence, a length of fabric in the form of a roll,
consisting of
a large number of sacks, is created, whereby the width of said length of
fabric
approximately corresponds to the depth of a sack:, but can also be double or a
multiple
of this depth in width. Should the width be double or a multiple of the depth
of the
sack, the strips are, however, arranged alongside: each other as mirror images
of each
other, whereby the centre selvedges (not shown) extending in the longitudinal
direction
of the fabric are located in the centre of fabric splicing strips 8 and/or
sack flaps or
shoulders 2 adjacent to each other. A double or multiple-width fabric is
preferably cut
apart along the longitudinal centre selvedge as soon as it leaves the loom.
Example C
of the production technology concerns the manufacture of a double-width length
of
fabric, in which both of the strips, the widl:h of each of which approximately
corresponds to the depth of a sack, are connected to each other in the area of
the fabric
splicing strip 8 forming the closed end of the sack, and which are open at
both their
long edges formed by the sack loops or the shoulders 2. The length of fabric
leaving
the loom is cut apart along the centre selvedge which extends along the middle
of the
fabric splicing strips 8 joined to each other in the middle by means of rotary
blades.
The fabric, the width of which approximately corresponds to the depth of a
sack, is cut
up at the centre selvedges 1 running straight across the fabric, immediately
if required,
in order to make individual sacks available straight away, or wound into
rolls, in which
form it can also be stored. The possibility then e:~cists for filling the
sacks on automatic
filling machines, particularly in large-scale commercial or industrial use.
After a sack
has been filled it is closed by sewing the sack flaps or shoulders 2 together
at the point
provided, and separated from the fabric at centre selvedge 1 by mechanical
rotary
blades.
H
